Episode Five
Series Episode Number: 297World Premiere: Sat 8 May 1971 - 6:13pm BST [BBC One] (United Kingdom)
Running Time: 25 minutes 22 seconds
8.80 Million (UK)
Chart Position: 23 () (UK)
Recorded on Fri 02 Apr 1971 in Television Centre 3
Archive State: RSC conver
With Jo held prisoner in his TARDIS, the Master forces the Doctor to take him to the underground city of the primitives. Any sign of treachery from the Doctor and Jo will die.